﻿
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<!-- saved from url=(0014)about:internet -->
<html xmlns:msxsl="urn:schemas-microsoft-com:xslt" xmlns:mssdk="winsdk" xmlns:script="urn:script" xmlns:build="urn:build" xmlns:MSHelp="http://msdn.microsoft.com/mshelp">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<meta name="Description" content="The !gs extension analyzes a /GS stack overflow."/>
<meta name="MSHAttr" content="PreferredSiteName:MSDN"/>
<meta name="MSHAttr" content="PreferredLib:/library/windows/hardware"/>
<title>!gs</title>

<meta name="MS-HAID" content="r24_exts_general_A_7288b132-9cdf-41a4-8435-d3231e26e76b.xml"/>


<link rel="STYLESHEET" type="text/css" HREF="../common/backsdk4.css"/>





<style>
html,div { margin: 0; padding: 0;}

body {
	padding: 0px;
	margin: 0px;
	overflow: auto;
	height: 100%;
}

#winchm_template_button{
	float: right;
	width: 93px;
	top: 7px;
	position: relative;
	text-align: right;
	right: 5px;
	height: auto;
}

#winchm_template_top{
	padding: 0px;
	margin: 0px;
	border-bottom: 1px solid #9B9B9B;
	background-color: #B1CEFE;
}

#winchm_template_navigation{
	margin: 0px;
	padding-top: 7px;
	padding-left: 7px;
	padding-bottom: 3px;
	padding-right: 0px;
	font-size: 8.5pt;
	font-family: Arial, Helvetica, sans-serif;
	font-weight: normal;
	color: #585858;
}

#winchm_template_title{
	margin: 0px;
	padding-top: 4px;
	padding-left: 7px;
	padding-bottom: 7px;
	padding-right: 0px;
	font-size: 18px; 
	font-family: Verdana, Geneva, sans-serif;
	color: #363636;
}

#winchm_template_content{
	margin-top: 20px;
	margin-left: 15px;
	margin-bottom: 20px;
	margin-right: 15px;
	width: auto  !important;
	width: 100%;
}

#winchm_template_footer{
	border-width: 1px;
	border-color: #B1CEFE;
	border-top-style: solid;
	margin-top: 15px;
	margin-left: 15px;
	margin-bottom: 20px;
	margin-right: 15px;
	padding-top: 7px;
	padding-left: 0px;
	padding-bottom: 0px;
	padding-right: 0px;
	font-family: arial, helvetica, sans-serif;
	font-size: 8.5pt;
	color: #696969;
	width: auto;
	text-align: left;
}


#winchm_template_container{
	margin: 0px;
	padding: 0px;
	position: static;
	padding-bottom: 3px;
	overflow: auto;
	background-color: #FFFFFF;
}


@media print
{
#winchm_template_container{
	position: static;	
	margin: 0px;
	padding: 5px;
	
	width: auto;
	height: auto;
	overflow: auto;
}
#winchm_template_button{
visibility:hidden;
}
}

#winchm_template_navigation A:link	{text-decoration: none; color:#004080}
#winchm_template_navigation A:visited  {text-decoration: none; color: #004080}
#winchm_template_navigation A:active {text-decoration: none; color: #004080 }
#winchm_template_navigation A:hover {text-decoration: none;color: #0080FF}

A:link	{text-decoration: underline; color:#0033CC}
A:visited  {text-decoration: underline; color: #0033CC}
A:active {text-decoration: underline; color: #0033CC }
A:hover {text-decoration: underline;color: #FF0000;}
</style>
<script type="text/javascript">
function isMobile(){
Agent = window.navigator.userAgent;
if (Agent.indexOf("iPhone")>=1 || Agent.indexOf("iPad")>=1 || Agent.indexOf("iPod")>=1 || Agent.indexOf("Android")>=1){
return true;
}else{
return false;	
}

}
function d_onresize(){
if (window.navigator.userAgent.indexOf("MSIE")>=1){
document.getElementById('winchm_template_container').style.pixelWidth = document.body.offsetWidth - 3;
document.getElementById('winchm_template_container').style.pixelHeight = document.body.offsetHeight - document.getElementById('winchm_template_top').offsetHeight - 4;
}
document.getElementById('winchm_template_container').style.top = document.getElementById('winchm_template_top').offsetHeight + 'px';
}

function d_onbeforeprint(){
document.getElementById('winchm_template_container').style.width = 'auto';
document.getElementById('winchm_template_container').style.height = 'auto';
}

function d_onafterprint(){
d_onresize();
}

if(!isMobile()){

window.onload = d_onresize;
window.onresize = d_onresize;
window.onbeforeprint = d_onbeforeprint;
window.onafterprint = d_onafterprint;

document.write("<style>\n");
document.write("body {overflow: hidden;}\n");
document.write("#winchm_template_container {position: absolute;overflow: auto;top : 0px;right: 0px;bottom: 0px;left: 0px;}\n");
document.write("</style>\n");
}

</script>
</head>
<body><script language="JavaScript" type="text/JavaScript">
function syn(){
if(parent.nav.tree){
 if(parent.nav.tree.loaded){
  parent.nav.tree.selectNode(2251);
 }else{
  setTimeout("syn()",500);
}
  }else{
  setTimeout("syn()",500);
  }}
if(parent!=self){
  setTimeout("syn()",100);
}else{
  parent.location.href = "../../index.htm?page=debugger/_gs.htm";
}
originalOnload = window.onload;
if(originalOnload==null){
window.onload = function(){parent.contentLoaded = true;};
}else{
window.onload = function(){originalOnload();parent.contentLoaded = true;};
}
</script> 


<div id="winchm_template_top">
	<div id="winchm_template_button"><A href="_gle.htm" title="Previous topic"><img id="winchm_template_prev" alt="Previous topic" src="../template2/btn_prev_n.gif" border="0"></a><A href="_handle.htm" title="Next topic"><img id="winchm_template_next" alt="Next topic" src="../template2/btn_next_n.gif" border="0"></a></div>
	<div id="winchm_template_navigation">Help &gt; 
<A href="introduction6.htm">Debugging Tools for Windows (WinDbg, KD, CDB, NTSD)</A> &gt; <A href="debugger_reference.htm">Debugger Reference</A> &gt; <A href="debugger_commands.htm">Debugger Commands</A> &gt; <A href="general_extensions.htm">General Extension Commands</A> &gt; </div>
	<div id="winchm_template_title">!gs</div>
</div>
<div id="winchm_template_container">
	<div id="winchm_template_content"><div id="mainSection"><p>The <b>!gs</b> extension analyzes a /GS stack overflow. </p>
<pre class="syntax"><b>!gs</b></pre>
<h3><a id="DLL"></a><a id="dll"></a>DLL</h3>
<table>
<tr>
<td>
<p><b>Windows 2000
         </b></p>
</td>
<td>
<p>
          Ext.dll
         </p>
</td>
</tr>
<tr>
<td>
<p><b>Windows XP and later
         </b></p>
</td>
<td>
<p>
          Ext.dll
         </p>
</td>
</tr>
</table>
<p> </p>
<h2>Remarks</h2>
<p>The <b>!gs</b>extension helps debug buffer overruns. Run <b>!gs</b>when you encounter a STATUS_STACK_BUFFER_OVERRUN error, as the following example shows.</p>
<pre class="syntax" xml:space="preserve"><code>0:000&gt; !gs
Corruption occurred in mshtml!CDoc::OnPaint or one of its callers
Real canary not found at 0x74866010
Canary at gsfailure frame 0x292ea4e7
Corrupted canary 0x0013e2c8: 0x00000000
Corrupted cookie value too generic, skipping init bit-flip check
a caller of mshtml!CDoc::OnPaint has corrupted the EBP from 0x0013e254 to 0x0013
e234
check callers (without canary) of mshtml!CDoc::OnPaint for 0x1 bytes of overflow

The canary doesn't look corrupted. Not sure how we got here
EBP/ESP check skipped: No saved EBP in exception context
Function mshtml!CDoc::OnPaint:
  00000000 - 00000004 this                      CDoc*
 0013de40 - 0013e180 rd                        CDoc::OnPaint::__l39::REGION_DAT
A
  0013e180 - 0013e18c Lock                      CDoc::CLock
  0013e18c - 0013e224 DI                        CFormDrawInfo
  0013e23c - 0013e240 hwndInplace               HWND__*
  0013e240 - 0013e244 prc                       tagRECT*
  0013e248 - 0013e250 ptBefore                  tagPOINT
  0013e250 - 0013e254 fViewIsReady              int
  0013e250 - 0013e254 fHtPalette                int
  0013e254 - 0013e258 fNoPaint                  int
  0013e258 - 0013e260 ptAfter                   tagPOINT
  0013e260 - 0013e264 c                         int
  0013e264 - 0013e268 hrgn                      HRGN__*
  0013e268 - 0013e2a8 ps                        tagPAINTSTRUCT
Candidate buffer : ps 0013e268 to 0013e2a7
  0013e268 ea 04 01 a7 00 00 00 00-10 01 00 00 f3 00 00 00 ................
  0013e278 ed 03 00 00 44 02 00 00-84 e5 13 00 f4 e2 13 00 ....D...........
  ...
  0013e2ac 38 20 01 03 10 e3 13 00-68 6b e6 01 d0 e6 03 00 8 ......hk......
 0013e2bc 80 fa 03 00 0d 00 00 00-10 08 19 00 00 00 00 00 ................
0:000&gt;</code></pre></div></div>	
	<div id="winchm_template_footer">Copyright &copy; 2019. All rights 
reserved. (To change the copyright info, just edit it in template.)</div>
</div>

</body>
</html>
